ASCP Recalls Questions & Answers 2026/2027 with Detailed
Rationales | Complete Exam-Style Questions | Graded A+ Pass
Guaranteed
SECTION I: CLINICAL CHEMISTRY
Question 1
A 24-year-old with type 1 diabetes presents with Kussmaul respirations. Laboratory
results show pH 7.15, glucose 480 mg/dL, and serum ketones weakly positive by
nitroprusside reaction. Which metabolite is the predominant contributor to the
metabolic acidosis?
A. Acetone
B. Acetoacetate
C. Beta-hydroxybutyrate
D. Lactic acid
Correct Answer: C. Beta-hydroxybutyrate
Rationale: In DKA, the redox shift favoring NADH drives ketogenesis toward
beta-hydroxybutyrate, which typically predominates at a 3:1 to 4:1 ratio over
acetoacetate. The standard nitroprusside method detects acetoacetate and acetone but
does not react with beta-hydroxybutyrate, explaining the weakly positive ketone result
despite severe acidosis.
Question 2
,A 55-year-old with jaundice has an isolated alkaline phosphatase of 420 U/L (reference
40–120). All other liver enzymes and bilirubin are normal. Which test best confirms the
hepatic origin of this elevated enzyme?
A. Alanine aminotransferase (ALT)
B. Gamma-glutamyl transferase (GGT)
C. Lactate dehydrogenase (LDH)
D. Aspartate aminotransferase (AST)
Correct Answer: B. Gamma-glutamyl transferase (GGT)
Rationale: GGT is highly specific for hepatobiliary tissue. While ALP is also produced by
bone, intestine, and placenta, an elevated GGT confirms the ALP is of liver origin. ALT,
AST, and LDH are present in multiple tissues and do not specifically distinguish hepatic
from bone-derived ALP.
Question 3
A patient on phenytoin for seizure disorder has a reported trough level of 8.2 mcg/mL
(therapeutic range 10–20 mcg/mL) drawn 4 hours after the morning dose. Which
statement is most accurate?
A. The result is subtherapeutic and the dose should be increased immediately.
B. The timing of the draw is inappropriate for trough interpretation.
C. Phenytoin follows first-order kinetics and the level is accurate.
D. The sample should be redrawn 2 hours after the next dose.
Correct Answer: B. The timing of the draw is inappropriate for trough interpretation.
Rationale: Trough levels for therapeutic drug monitoring must be drawn immediately
before the next scheduled dose. A sample drawn 4 hours after dosing does not
represent the minimum concentration and cannot be reliably interpreted. Phenytoin
exhibits zero-order (saturation) kinetics at therapeutic concentrations, making timing
even more critical.
,Question 4
Arterial blood gas results: pH 7.32, pCO2 30 mmHg, HCO3 15 mEq/L. What is the
primary acid-base disturbance?
A. Metabolic acidosis with appropriate respiratory compensation
B. Respiratory alkalosis with metabolic compensation
C. Mixed metabolic and respiratory acidosis
D. Uncompensated metabolic acidosis
Correct Answer: A. Metabolic acidosis with appropriate respiratory compensation
Rationale: The pH is low (acidemia) and the bicarbonate is reduced, indicating a primary
metabolic acidosis. Using Winter's formula, the expected compensatory pCO2 = (1.5 ×
15) + 8 = 30.5 ± 2 mmHg. The measured pCO2 of 30 mmHg falls within this expected
range, confirming appropriate respiratory compensation rather than a mixed disorder.
Question 5
A patient presents with fatigue and constipation. Laboratory results show calcium 12.8
mg/dL, phosphorus 2.2 mg/dL, and intact PTH 88 pg/mL (elevated). What is the most
likely diagnosis?
A. Primary hyperparathyroidism
B. Malignancy-associated hypercalcemia
C. Vitamin D intoxication
D. Secondary hyperparathyroidism
Correct Answer: A. Primary hyperparathyroidism
Rationale: Primary hyperparathyroidism is characterized by hypercalcemia with an
inappropriately elevated or normal PTH level, indicating autonomous secretion. In
malignancy and vitamin D intoxication, PTH is typically suppressed by negative
feedback. Secondary hyperparathyroidism presents with elevated PTH but
hypocalcemia.
, Question 6
A patient with chest pain has normal CK-MB and total CK at 8 hours post-presentation,
but cardiac troponin-I is markedly elevated. Which statement best explains this pattern?
A. The patient has skeletal muscle injury.
B. The elevated troponin-I indicates myocardial infarction.
C. The sample was drawn too early for CK-MB detection.
D. Laboratory error is likely because CK-MB should always be elevated before troponin.
Correct Answer: B. The elevated troponin-I indicates myocardial infarction.
Rationale: Cardiac troponins rise within 3–6 hours after myocardial injury and remain
elevated for 7–10 days. CK-MB rises slightly later and normalizes within 2–3 days. An
elevated troponin-I with normal CK-MB at 8 hours is consistent with acute MI and
demonstrates the superior sensitivity and specificity of troponin for myocardial injury.
Question 7
An overnight 1 mg dexamethasone suppression test shows a post-dexamethasone
cortisol of 24 mcg/dL (reference <1.8 mcg/dL). The ACTH level is 52 pg/mL (elevated).
What is the most likely cause of Cushing syndrome?
A. Adrenal adenoma
B. Pituitary adenoma (Cushing disease)
C. Ectopic ACTH syndrome
D. Exogenous corticosteroid use
Correct Answer: B. Pituitary adenoma (Cushing disease)
Rationale: Failure to suppress cortisol after low-dose dexamethasone confirms Cushing
syndrome. An elevated ACTH level indicates ACTH-dependent disease. While ectopic
ACTH can also elevate ACTH, pituitary adenoma (Cushing disease) is the most
common cause of ACTH-dependent Cushing syndrome. Adrenal adenomas cause
ACTH-independent disease with suppressed ACTH.
Rationales | Complete Exam-Style Questions | Graded A+ Pass
Guaranteed
SECTION I: CLINICAL CHEMISTRY
Question 1
A 24-year-old with type 1 diabetes presents with Kussmaul respirations. Laboratory
results show pH 7.15, glucose 480 mg/dL, and serum ketones weakly positive by
nitroprusside reaction. Which metabolite is the predominant contributor to the
metabolic acidosis?
A. Acetone
B. Acetoacetate
C. Beta-hydroxybutyrate
D. Lactic acid
Correct Answer: C. Beta-hydroxybutyrate
Rationale: In DKA, the redox shift favoring NADH drives ketogenesis toward
beta-hydroxybutyrate, which typically predominates at a 3:1 to 4:1 ratio over
acetoacetate. The standard nitroprusside method detects acetoacetate and acetone but
does not react with beta-hydroxybutyrate, explaining the weakly positive ketone result
despite severe acidosis.
Question 2
,A 55-year-old with jaundice has an isolated alkaline phosphatase of 420 U/L (reference
40–120). All other liver enzymes and bilirubin are normal. Which test best confirms the
hepatic origin of this elevated enzyme?
A. Alanine aminotransferase (ALT)
B. Gamma-glutamyl transferase (GGT)
C. Lactate dehydrogenase (LDH)
D. Aspartate aminotransferase (AST)
Correct Answer: B. Gamma-glutamyl transferase (GGT)
Rationale: GGT is highly specific for hepatobiliary tissue. While ALP is also produced by
bone, intestine, and placenta, an elevated GGT confirms the ALP is of liver origin. ALT,
AST, and LDH are present in multiple tissues and do not specifically distinguish hepatic
from bone-derived ALP.
Question 3
A patient on phenytoin for seizure disorder has a reported trough level of 8.2 mcg/mL
(therapeutic range 10–20 mcg/mL) drawn 4 hours after the morning dose. Which
statement is most accurate?
A. The result is subtherapeutic and the dose should be increased immediately.
B. The timing of the draw is inappropriate for trough interpretation.
C. Phenytoin follows first-order kinetics and the level is accurate.
D. The sample should be redrawn 2 hours after the next dose.
Correct Answer: B. The timing of the draw is inappropriate for trough interpretation.
Rationale: Trough levels for therapeutic drug monitoring must be drawn immediately
before the next scheduled dose. A sample drawn 4 hours after dosing does not
represent the minimum concentration and cannot be reliably interpreted. Phenytoin
exhibits zero-order (saturation) kinetics at therapeutic concentrations, making timing
even more critical.
,Question 4
Arterial blood gas results: pH 7.32, pCO2 30 mmHg, HCO3 15 mEq/L. What is the
primary acid-base disturbance?
A. Metabolic acidosis with appropriate respiratory compensation
B. Respiratory alkalosis with metabolic compensation
C. Mixed metabolic and respiratory acidosis
D. Uncompensated metabolic acidosis
Correct Answer: A. Metabolic acidosis with appropriate respiratory compensation
Rationale: The pH is low (acidemia) and the bicarbonate is reduced, indicating a primary
metabolic acidosis. Using Winter's formula, the expected compensatory pCO2 = (1.5 ×
15) + 8 = 30.5 ± 2 mmHg. The measured pCO2 of 30 mmHg falls within this expected
range, confirming appropriate respiratory compensation rather than a mixed disorder.
Question 5
A patient presents with fatigue and constipation. Laboratory results show calcium 12.8
mg/dL, phosphorus 2.2 mg/dL, and intact PTH 88 pg/mL (elevated). What is the most
likely diagnosis?
A. Primary hyperparathyroidism
B. Malignancy-associated hypercalcemia
C. Vitamin D intoxication
D. Secondary hyperparathyroidism
Correct Answer: A. Primary hyperparathyroidism
Rationale: Primary hyperparathyroidism is characterized by hypercalcemia with an
inappropriately elevated or normal PTH level, indicating autonomous secretion. In
malignancy and vitamin D intoxication, PTH is typically suppressed by negative
feedback. Secondary hyperparathyroidism presents with elevated PTH but
hypocalcemia.
, Question 6
A patient with chest pain has normal CK-MB and total CK at 8 hours post-presentation,
but cardiac troponin-I is markedly elevated. Which statement best explains this pattern?
A. The patient has skeletal muscle injury.
B. The elevated troponin-I indicates myocardial infarction.
C. The sample was drawn too early for CK-MB detection.
D. Laboratory error is likely because CK-MB should always be elevated before troponin.
Correct Answer: B. The elevated troponin-I indicates myocardial infarction.
Rationale: Cardiac troponins rise within 3–6 hours after myocardial injury and remain
elevated for 7–10 days. CK-MB rises slightly later and normalizes within 2–3 days. An
elevated troponin-I with normal CK-MB at 8 hours is consistent with acute MI and
demonstrates the superior sensitivity and specificity of troponin for myocardial injury.
Question 7
An overnight 1 mg dexamethasone suppression test shows a post-dexamethasone
cortisol of 24 mcg/dL (reference <1.8 mcg/dL). The ACTH level is 52 pg/mL (elevated).
What is the most likely cause of Cushing syndrome?
A. Adrenal adenoma
B. Pituitary adenoma (Cushing disease)
C. Ectopic ACTH syndrome
D. Exogenous corticosteroid use
Correct Answer: B. Pituitary adenoma (Cushing disease)
Rationale: Failure to suppress cortisol after low-dose dexamethasone confirms Cushing
syndrome. An elevated ACTH level indicates ACTH-dependent disease. While ectopic
ACTH can also elevate ACTH, pituitary adenoma (Cushing disease) is the most
common cause of ACTH-dependent Cushing syndrome. Adrenal adenomas cause
ACTH-independent disease with suppressed ACTH.
